Solution:
Get XpdfReader PDF software which can open a malformed PDF files!
For more information about internal structure of PDFs
Test 1:
In the following sample file, the file starts with malformed PDF file signature
%P!F- which is incorrect and should be %PDF-, as seen in FRHED editor.
XpdfReader is the only app I came across that could open this file with this first malformed change.
Test 2:
Then I remove leading angle bracket < where there should be two for <<Lineralired, and it opened!
Source
The original unadulterated file header is
%PDF-1.5%<bh:e2><bh:e3><bh:cf><bh:d3>10 0 obj\<</Linearized 1/L 105981/O 12/E 101484/N 1/T 105677/H [ 502 173]>>endobj
For more information about internal structure of PDFs
Example of absolute minimal PDF file contents "Hello World", copy and pasted into FHRED.
%PDF-1.1 1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj 2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj 3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 200 200] /Contents 4 0 R /Resources << /Font << /F1 5 0 R >> >> >> endobj 4 0 obj << /Length 44 >> stream BT /F1 12 Tf 72 100 Td (Hello World) Tj ET endstream endobj 5 0 obj << /Type /Font /Subtype /Type1 /BaseFont /Helvetica >> endobj xref 0 6 0000000000 65535 f 0000000009 00000 n 0000000056 00000 n 0000000107 00000 n 0000000212 00000 n 0000000310 00000 n trailer << /Size 6 /Root 1 0 R >> startxref 380 %%EOF
Here's Hello World.pdf opened in XpdfReader 4.06
